(a) Field of the Invention
The present invention generally relates to the monitoring of the quality of the raw-milk which is produced and stored on dairy farms, and includes both systems and methods which are concerned herewith.
(b) Background Art
Raw milk from cows which is harvested with “milking” equipment on dairy farms is generally transferred via a network of piping, pumps, filters and possible heat exchangers into one or more storage tanks which are located on the dairy farm. Such harvesting sessions usually occur several times daily. The raw milk which has been transferred into the storage tank should be cooled to a predefined industry standard temperature for raw milk storage, within an industry specified time frame, as specified by certain regulatory bodies. Generally, raw milk is stored at temperatures no higher than 38° F. (3° C.) to ensure that small amounts of bacteria already existing in raw milk does not proliferate and degrade the quality of milk prior to transport to a processing plant.
The storage tanks on the dairy farm generally consist of a double-walled, insulated, stainless steel vessel. Some storage tanks may have an evaporator plate fixed to the outside of the inner stainless steel wall of the storage tank, through which a refrigerant is circulated as the means to remove the heat from the raw milk which is stored in the tank. Milk storage tanks without fixed cooling apparatus are also common, in which case the milk is cooled to the storage temperature for raw milk prior to entry into the storage tank.
The storage tank is charged with raw milk from one of any number of daily milking sessions, depending on the size of the cow herd and the number of times each cow is milked per day. At regular intervals (typically but not limited to once every 2 days) the raw milk is transferred to a milk transport truck for transport to a processing plant. Once empty, the storage tank is washed, sanitized and rinsed in preparation for subsequent storage of the next milking sessions. Typically this “clean-in-place” (CIP) procedure automatically circulates, first, a clear water rinse followed by detergent solution (usually alkaline) during which the cleaning solution must maintain a temperature above a specified threshold (determined by the blend of cleaning chemicals) for a specified minimum period of time, generally a minimum of 110° F. (38° C.) for no less than 4 to 9 minutes. Following the detergent cleaning cycle, an acid solution is circulated. In some cases, a final cold or tepid water rinse is used.
Occasionally operational errors of various kinds can occur during the cleaning cycle. It is not uncommon for the detergent cleaning solution to fall below the minimum temperature threshold and thereby to compromise the cleaning process. In other cases, various automatic mechanical cleaning equipment may malfunction, thereby compromising the cleaning cycle in various ways. Human error is also frequently a factor for failed cleaning processes.
Some time after the “clean-in-place” procedure has been completed (with or without mechanical or human failure), the dairy farmer or herdsman (the “operator”), would normally commence the next milk harvesting session during which raw milk will once again be transferred from the collection equipment to the storage tank. Typically, milk harvesting and cooling/storage equipment require some degree of manual operation, varying with location. Typically, operators are required to energize the milk harvesting and the cooling equipment circuits. Timing of procedures varies both within, and by location, and also by equipment configuration and brands. Freshly harvested raw milk from this first session must now be cooled within given allowable time periods. When the storage tank/condensing unit circuit is energized, the milk begins to cool to the required storage temperature. Typically, once the cooling circuit is energized, a control thermostat will “call” for cooling, causing the condensing unit to operate, thereby circulating liquid refrigerant though heat exchangers. Refrigerant “boiling off” in the heat exchangers will draw the heat from the warm milk. On some farms, milk may be partially or fully cooled prior to transfer into the storage tank, using various models of heat exchangers. After a variable amount of time, a milk harvesting session will finish. Typically, the cooling cycle will continue past the completion of the milking session until the temperature inside the storage tank is at the required level and the control thermostat automatically de-energizes the condensing unit.
At any time after the first session and before the next session, the control thermostat may call for cooling if the temperature of the raw milk rises above the recommended storage temperature. The control thermostat will continue to control the cooling process until the storage tank is again emptied at which time the cooling circuit will be energized.
At the start of a second milking session, the procedure begins in the same manner as the above-described first milking session. The operator starts the milk harvesting equipment. In many cases, new warm raw milk from the second milking session is collected for storage, and is diluted with the cooled milk from previous session or sensors, creating a blended temperature. The condensing unit circuit will be energized when the temperature inside the storage tank rises above the control thermostat set point. Sometime after the second milking session is over, blended milk will be cooled to the storage temperature and the thermostat will de-energize the condensing unit circuit.
Subsequent sessions will be completed until the stored raw milk is collected for transport to the processing plant. Immediately after the tank is emptied, a cleaning cycle is completed, and the collection/storage/cleaning cycle will repeat itself.
Throughout this procedure, any number of operator or mechanical errors can occur. Any one of these errors or combination of errors can cause less than optimal conditions for the storage of raw milk. Less than ideal storage conditions of raw milk will exponentially increase the level of bacterial growth in the stored raw milk causing the quality of the raw milk to decrease and in some cases to be rendered totally un-saleable. While in some cases the sub-optimal raw milk may still be used in certain procedures not requiring optimal quality raw milk, it is becoming the norm that the entire quantity of raw milk which is held in the storage tank be discarded as waste and the revenue to the dairy farmer is thus permanently lost.
The quality of the raw milk in the storage tank will be subjected to several qualitative tests prior to acceptance for processing. The transport truck driver will visually inspect the milk, smell the milk and in some cases taste it. If the transport driver decides the milk is of poor quality, he may refuse to collect the milk and the stored milk will be dumped. Oral subjective testing is an inexact science and tends to put undue pressure on the tester. After passing the oral test, a sample of raw milk is collected for subsequent random laboratory testing for conditions in the raw milk that cannot be detected by the oral qualitative tests. A storage tank of raw milk may pass the qualitative tests on the farm but later be found to have been of poor quality. This will result in a warning being issued, possibly a penalty levied, and depending on recent history, the producers right to ship milk may be suspended until the cause of the infraction is identified and corrected.
To aid in the monitoring and evaluating of stored milk there are currently various makes and models of analog and digital data loggers that can be attached to the storage tank to “log” the ambient temperatures of the storage tank. Some models may also record the temperatures of the milk harvesting cleaning cycles. This information is used as proof of the actual temperatures of the raw milk in the storage tank over the specified period of time between milk pick ups. The operator and the milk transport truck driver or other agent of the regulatory body can then review the conditions of the raw milk in that specified period of time to assist in the qualitative judging of the quality of the raw milk stored in that particular storage tank. Conventional data loggers and some model of storage tanks can also be equipped with audible or visual alarms that will notify the operator of any conditions that are detected to be outside a preset range of temperatures in the storage tank.
Current alarm systems and data loggers, however useful, have many shortfalls. Pre-occupied, un-responsible, or absent operators are common. Data loggers are not routinely checked and faulty storage conditions of the raw milk can go undetected until the transport driver checks the data logger. Faulty storage conditions occurring during the initial harvesting session when not promptly detected, will contaminate subsequent fresh milk introduced for storage. Many regions of the dairy industry are now considering formalizing the data logging activity. In certain jurisdictions, regulatory bodies are testing the reliability of data logging equipment with a view to making it mandatory to have a data logger on the storage tank to record both the temperature of the raw milk in the storage tank between pick ups and the temperatures of the cleaning cycles.
(c) Description of the Prior Art
Among the patent literature relating to the above-referred-to apparatus and methods to monitor the quality of milk are the following:
U.S. Pat. No. 4,455,483, patented Jun. 19, 1984, by M. J. Schönhuber which was directed to a system for recording data relating to specific lots of milk. The data were collected at delivery locations by a collecting vehicle and were brought by the vehicle to a collecting station. The system included a recorder in the vehicle. The recorder included data input means, a controlled unit means and memory means. The system further included a collecting station where data from the vehicle was converted and stored on two different data carriers. The system further included stationary data processing units which received the data from the two different data carrying units in the collecting stations.
U.S. Pat. No. 4,612,537, patented Sep. 16, 1986, by A. Maltairs et al, which was directed to an alarm system for monitoring the temperature of a liquid contained in a reservoir. The system included a temperature sensing probe for sensing the temperature of the liquid. A sensing circuit was associated with the probe to generate a temperature-indicating signal which was representative of the liquid temperature. A calibration circuit was provided for calibrating the temperature signal relative to a reference signal. Converter means was provided to convert the calibrated temperature signal to a binary signal which was indicative of sensed temperatures of the liquid. This fed comparator circuits having pre-set limit detectors to initiate an alarm signal when the temperature signal exceeded a predetermined value. The comparator circuits also fed a display device to indicate the temperature of the liquid.
U.S. Pat. No. 4,710,755, patented Dec. 1, 1987, by R. A. Gurney, which was directed to an alarm for a milk cooler, which sounded an alarm when the temperature of milk within the cooler exceeded a predetermined value. A switch permitted the device to be turned off to prevent it from sounding such alarm when milk was being discharged from the cooler, or when the cooler was being cleaned with hot cleaning solvent. However, when fresh milk was being introduced into the cooler, that switch was overridden and the alarm sounded should the milk not be cooled to the required temperature after a predetermined interval of time.
U.S. Pat. No. 5,743,209, patented Apr. 28, 1998, by S. Bazin et al, which was directed to a system and method for monitoring and controlling milk production at dairy farms. That patent provided an automated modular system, whose operation provided a method for officially controlling the quantity and quality of milk production at a dairy farm site. The method included the first steps of assigning each dairy herd an identification code and also assigning each milk producing animal in each herd a unique animal identification code. The quantitative milk production from an individual animal was measured using a milk flow meter which was temporarily connectable with a milking machine for an individual animal. The milk flow meter was capable of continuously weighing milk produced per unit time by an individual animal during a single milking session. A qualitative analysis of the composition of a sample of milk from an individual dairy animal was provided. Such analysis included an infra-red optical probe. A system control and memory was connected to the milk flow meter and to the qualitative analysis. A dairy herd code was entered into the system control and thereby initiated control of the herd and accessing stored data for herd and each individual dairy animal therein. An individual dairy animal identification code was entered in the system control when the corresponding individual dairy animal was present at the milking machine, thereby activating the milk flow meter. Quantitative milk production from the individual dairy animal was measured. A sample of milk from the individual dairy animal was quantitatively analyzed. Completion of milking session as indicated by milk flow meter was detected, and memory data from the milking session was stored in the system.
U.S. Pat. No. 5,996,529, patented Dec. 7, 1999, by K. L. Sisson et al, which was directed to a milk metering and cow I.D. system, for use in a milking parlor having a plurality of stalls. The system monitored milk production and identified each of a plurality of animals being milked. A plurality of milk metering subsystems was included, each of which was assigned to one of a plurality of stalls. The milk metering subsystem sensed the temperature of milk and/or wash flowing through the milk metering subsystem. A host computer managed both the flow of data throughout the system and the operation of the milk metering subsystems by way of a remotely-located system interface between the computer and each of the milk metering subsystems. An RS-485 connection between each of the plurality of milk metering subsystems and system interface was included. The system also included at least one antenna which received animal identification data for each of the animals being milked and electrically communicated that identification data the host computer. A plurality of transponders was included in which one was located on an ear of each monitored animals. A receiver was also provided for each stall. Milk production data was automatically transferred to the host computer after the expiration of a time period following a triggering even, at the end of a shift, or on demand.
U.S. Pat. No. 6,006,615, patented Dec. 28, 1999, by M. J. Uttinger, which was directed to a remote data acquisition system, which included a sensor into a storage device. The sensor was capable of sensing at least one parameter, e.g., the temperature of the material stored in the storage device. The remote data acquisition system also included transmission means associated with the sensor and which was capable of outputting the information sensed by the sensor, or a data storage device to store the information sensed. That patent also provided a method of allocating the type of processing accorded to material collected from a storage device. In carrying out such method, the storage device incorporated at least one sensor which was capable of reading parameters, e.g., temperatures of material held within the storage device. The method included the steps of outputting the information sensed from the sensor to a central processing station, and using the output information to coordinate the type of processing accorded in the material within the storage device.
According to that patentee, while the primary parameter sensed by the sensor was temperature, other parameters, e.g., the acidity of the milk, its density, conductivity, turbidity or perhaps fat content, may be sensed instead of, or in addition to temperature. According to that patentee, one could monitor the electrical network. This was alleged to highlight any inadequate power supplies. Monitoring of voltage/current demands on the dairy hot water system used for cleaning purposes was alleged to provide proof of water temperature. However, because of inherent faults, this monitoring only provides a rough indirect estimate of the temperatures throughout the system.
That patentee alleged that measuring the voltage/current demands to the farm dairy pumping system responsible for movement of milk from producing dairy cow through to the milk vat would provide a measure of the milk flow. However, because of inherent faults, this measuring only provided a rough indirect estimate of the milk flow.
That patentee also suggested monitoring the clean-in-place (CIP) equipment along with its efficiencies. For example, it was suggested by that patentee that water temperature and volumes could be monitored to ensure food hygiene standards were met with the automated CIP system, or with alternative methods used for cleaning milking machinery. However, there was no teaching of any alarm system to report failure of the CIP procedure.
That patentee also suggested that the temperature of the water supplied or used in relation to the refrigeration system be monitored. The patentee thus suggested taking temperature readings of water both entering and exiting the chiller system. However, there was no teaching of any alarm to warn of any inadequacy of the cooling system should the measured temperature of the water be outside the predetermined upper and lower temperatures.
Thus, the above prior art leaves many other problems to be addressed.
As a further development, the dairy industry is studying the use of Hazard and Critical Control Points standards (“HACCP”) which are geared to a dairy farm operation and environment. HACCP standards are currently in use at processing plants. Such standards involve the documentation of compliance with raw milk handling, cleaning/sanitation routines [i.e., clean-in-place] and other dairy farm management standards.